miller league?
I wouldn't want to watch any of them, not even out of curiosity. All the cancelled projects sound like disasters that we're very lucky never happened.
George Millers - Justice League. Was days away from shooting in 2007
I'll expand a bit
SUPERMAN LIVES - Directed By Tim Burton - Starring Nic Cage - Superman squares off against polar bears, giant spiders - CAN'T FLY - and has a wise-cracking, gay (?) midget robot.
SUPERMAN: FLYBY - Written maybe directed by J.J Abrams - An 'exciting' reboot of Superman. Krypton still exists, is in civial war. Superman dies and Jor El's kills himself by stabbing himself in the stomach to tell Superman he can't die in Krypton Heaven.
BATMAN: YEAR ONE - Directed by Darren Afronsky - Bruce is homeless after his parents are killed. Alfred is an african-american called "Little Al" who runs an auto-repair shop and trains Bruce.
BATMAN TRIUMPHANT - Directed By Joel Schumacher - Starring George Clooney - Batman squares off against Scarecrow. The Joker would return as a hallucination in Batman's mind caused by the Scarecrow's fear toxin. Harley Quinn appeared as a supporting character, written as the Joker's daughter trying to get revenge on Batman for the Joker's death. Schumacher wanted Nicholas Cage or Jeff Goldblum for Scarcrow and Madonna for Harley. Jack Nicholson would cameo as The Joker.
BATMAN VS. SUPERMAN - Starring Christian Bale and Josh Hartnett - Batman is retired and about to get married. After his wife is killed, Superman warns him about the dangers of revenge. Joker is resurrected by Lex Luthor.
THE JUSTICE LEAGUE - Directed by George Miller - Starring Armie Hammer, DJ Cortana, Adam Brody etc - Based loosely on The Tower of Babel, and hinting that its post the events of the Nolanverse (it mentions Ras losing) Batman in his paranoid self sets up a satillete system to keep an eye on the Justice League and document their weaknesses. But somebody else has other plans...
SUPERMAN RETURNS 2 - DIrected by Bryan Singer - Starring Brandon Routh - Singer described this as his "Wrath of Khan" and would have centered around Brainiac who would have originally been from Krypton. He would have followed Superman back to Earth from the remnants of Krypton during his five year trip. Also, the bank robber who shot Superman in the eye around the middle of the first film would turn out to be John Corben, a.k.a. Metallo for the sequel.
Someone of these details are probably totally wrong but you get a rough idea.
YOU CAN ONLY WATCH ONE, ONE TIME.